It looks like the band is all but locking into the band. The first thing I would try: loosen the recoil plate screw enough that it still snug but not real tight. Lay a piece of carpet on a concrete floor. Then with one hand around the stock and handguard and the other on the barrel band pushing down strike the buttplate on the carpet. You may have to try it a couple times to get to catch. Then retighten the recoil plate screw.

That will usually prevent the handguard from being too loose.

John